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https://www.readbyqxmd.com/read/29149566/iedda-reaction-of-molecular-iodine-catalyzed-synthesis-of-1-3-5-triazines-via-functionalization-of-sp-3-c-h-bond-of-acetophenones-with-amidines-an-experimental-investigation-and-dft-study
#1
Abhishek Rajesh Tiwari, Shilpa Raveendra Nath, Kaustubh Ashok Joshi, Bhalchandra Mahadeo Bhanage
The present work reports an inverse electron demand Diels Alder (iEDDA) type reaction to synthesize 1,3,5-trizines from acetophenones and amidines. The use of molecular iodine in catalytic amount facilitates the functionalization of sp3 C-H bond of acetophenones. This is a simple and efficient methodology for the synthesis of 1,3,5-triazines in good to excellent yields under transition metal-free and peroxide-free conditions. The reaction is believed to take place via an in situ iodination-based oxidative elimination of formaldehyde...
November 17, 2017: Journal of Organic Chemistry
https://www.readbyqxmd.com/read/29147638/a-sensitive-and-rapid-method-for-detecting-formaldehyde-in-brain-tissues
#2
Xiangpei Yue, Yaoyue Zhang, Wen Xing, Yutong Chen, Chenyang Mu, Zhan Miao, Peichun Ge, Tingting Li, Rongqiao He, Zhiqian Tong
The existing methods for detecting formaldehyde (FA) in brain samples are expensive and require sophisticated experimental procedures. Here, we established a highly sensitive and selective spectrophotometric method, which is based on a reaction in which FA reacts with colorless reagent 4-amino-3-penten-2-one (Fluoral-P) to produce a yellow compound, 3,5-diacetyl-1,4-dihydrolutidine (DDL), which can be detected by a spectrophotometer at 420 nm at room temperature. The sensitive response time point was found to be at the first hour, and the optimal pH of derivative reaction was pH 6...
2017: Analytical Cellular Pathology (Amsterdam)
https://www.readbyqxmd.com/read/29146773/glyoxal-as-an-alternative-fixative-to-formaldehyde-in-immunostaining-and-super-resolution-microscopy
#3
Katharina N Richter, Natalia H Revelo, Katharina J Seitz, Martin S Helm, Deblina Sarkar, Rebecca S Saleeb, Elisa D'Este, Jessica Eberle, Eva Wagner, Christian Vogl, Diana F Lazaro, Frank Richter, Javier Coy-Vergara, Giovanna Coceano, Edward S Boyden, Rory R Duncan, Stefan W Hell, Marcel A Lauterbach, Stephan E Lehnart, Tobias Moser, Tiago Outeiro, Peter Rehling, Blanche Schwappach, Ilaria Testa, Bolek Zapiec, Silvio O Rizzoli
Paraformaldehyde (PFA) is the most commonly used fixative for immunostaining of cells, but has been associated with various problems, ranging from loss of antigenicity to changes in morphology during fixation. We show here that the small dialdehyde glyoxal can successfully replace PFA Despite being less toxic than PFA, and, as most aldehydes, likely usable as a fixative, glyoxal has not yet been systematically tried in modern fluorescence microscopy. Here, we tested and optimized glyoxal fixation and surprisingly found it to be more efficient than PFA-based protocols...
November 16, 2017: EMBO Journal
https://www.readbyqxmd.com/read/29145141/characterizing-pollutant-emissions-from-mosquito-repellents-incenses-and-implications-in-risk-assessment-of-human-health
#4
Lina Wang, Xinran Zheng, Svetlana Stevanovic, Zhiyuan Xiang, Jing Liu, Huiwen Shi, Jing Liu, Mingzhou Yu, Chun Zhu
Mosquito-repellent incense is one of the most popular products used for dispelling mosquitos during summer in China. It releases large amounts of particulate and gaseous pollutants which constitute a potential hazard to human health. We conducted chamber experiment to characterize major pollutants from three types of mosquito-repellent incenses, further assessed the size-fractionated deposition in human respiratory system, and evaluated the indoor removing efficiency by fresh air. Results showed that the released pollutant concentrations were greater than permissible levels in regulations in GB3095-2012, as well as suggested by the World Health Organization (WHO)...
October 22, 2017: Chemosphere
https://www.readbyqxmd.com/read/29145133/simultaneous-treatment-of-dimethyl-disulfide-and-hydrogen-sulfide-in-an-alkaline-biotrickling-filter
#5
Luis Arellano-García, Sylvie Le Borgne, Sergio Revah
Foul odors comprise generally a complex mixture of molecules, where reduced sulfur compounds play a key role due to their toxicity and low odor threshold. Previous reports on treating mixtures of sulfur compounds in single biofilters showed that hydrogen sulfide (H2S) interferes with the removal and degradation of other sulfur compounds. In this study, hydrogen sulfide (H2S) and dimethyl disulfide (DMDS) were fed to an alkaline biotrickling filter (ABTF) at pH 10, to evaluate the simultaneous removal of inorganic and organic sulfur compounds in a single, basic-pH system...
October 17, 2017: Chemosphere
https://www.readbyqxmd.com/read/29143782/sustainable-bio-based-phenol-formaldehyde-resoles-using-hydrolytically-depolymerized-kraft-lignin
#6
Homaira Siddiqui, Nubla Mahmood, Zhongshun Yuan, Ferdinando Crapulli, Luana Dessbesell, Amin Rizkalla, Ajay Ray, Chunbao Charles Xu
In this study bio-based bio-phenol-formaldehyde (BPF) resoles were prepared using hydrolytically depolymerized Kraft lignin (DKL) as bio-phenol to partially substitute phenol. The effects of phenol substitution ratio, weight-average molecular weight (Mw) of DKL and formaldehyde-to-phenol (F/P) ratio were also investigated to find the optimum curing temperature for BPF resoles. The results indicated that DKL with Mw ~ 1200 g/mol provides a curing temperature of less than 180 °C for any substitution level, provided that F/P ratios are controlled...
October 28, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/29140697/accurate-excited-state-geometries-a-caspt2-and-coupled-cluster-reference-database-for-small-molecules
#7
Simon Budzak, Giovanni Scalmani, Denis Jacquemin
We present an investigation of the excited-state structural parameters determined for a large set of small compounds with the dual goals of defining reference values for further works and assessing the quality of the geometries obtained with relatively cheap computational approaches. In the first stage, we compare the excited-state geometries obtained with ADC(2), CC2, CCSD, CCSDR(3), CC3 and CASPT2 and large atomic basis sets. It is found that CASPT2 and CC3 results are generally in very good agreement with one another (typical differences of ca...
November 15, 2017: Journal of Chemical Theory and Computation
https://www.readbyqxmd.com/read/29139137/potential-exposure-and-cancer-risk-from-formaldehyde-emissions-from-installed-chinese-manufactured-laminate-flooring
#8
Patrick Sheehan, Ankur Singhal, Kenneth T Bogen, David MacIntosh, Renee M Kalmes, John McCarthy
Lumber Liquidators (LL) Chinese-manufactured laminate flooring (CLF) has been installed in >400,000 U.S. homes over the last decade. To characterize potential associated formaldehyde exposures and cancer risks, chamber emissions data were collected from 399 new LL CLF, and from LL CLF installed in 899 homes in which measured aggregate indoor formaldehyde concentrations exceeded 100 μg/m(3) from a total of 17,867 homes screened. Data from both sources were combined to characterize LL CLF flooring-associated formaldehyde emissions from new boards and installed boards...
November 15, 2017: Risk Analysis: An Official Publication of the Society for Risk Analysis
https://www.readbyqxmd.com/read/29139119/effect-of-sterilants-on-amplification-and-detection-of-target-dna-from-bacillus-cereus-spores
#9
James M Robertson, Douglas L Anders, Francene Basalyga, Julie Millar, Donia Palomo Slack, Robert Bever
To conceal criminal activity of a bioterrorist or agroterrorist, the site of pathogen generation is often treated with sterilants to kill the organisms and remove evidence. As dead organisms cannot be analyzed by culture, this study examined whether DNA from sterilant-treated Bacillus cereus spores was viable for amplification. The spores were exposed to five common sterilants: bleach, Sterilox®, oxidizer foam (L-Gel), a peroxyacid (Actril®), and formaldehyde vapor. The spores were inoculated on typical surfaces found in offices and laboratories to test for environmental effects...
November 15, 2017: Journal of Forensic Sciences
https://www.readbyqxmd.com/read/29137699/determination-of-sulfite-in-food-by-liquid-chromatography-tandem-mass-spectrometry-collaborative-study
#10
Katherine S Carlos, Lowri S de Jager
Sulfites are added to a wide range of food and beverage products to prevent browning or oxidation. Although most of the population do not experience side effects from consuming sulfites, a small subset has been shown to experience an "allergic-like" response. For this reason, the U.S. Food and Drug Administration requires that sulfites be labeled on all products that contain more than 10 mg/kg (parts per million) sulfur dioxide. The current regulatory method, optimized Monier-Williams (OMW) Official Method 990...
November 1, 2017: Journal of AOAC International
https://www.readbyqxmd.com/read/29137685/nutrition-research-in-cognitive-impairment-dementia-with-a-focus-on-soya-and-folate
#11
Eef Hogervorst, Shelina Kassam, Atik Kridawati, Mira Soni, Xu Xin, Xiao Shifu, Tri Budi Rahardjo
Observational studies and treatment trials investigating nutrition and cognitive function, with a focus on folate and soya and dementia, were reviewed. Data suggested that effects of folic acid based interventions may only be shown before cognitive decline is evident and/or if people are folate deficient. In older people in Indonesia, Hawai'i and China, tofu, which can contain high levels of phytoestrogens, was found to increase dementia risk. This association was not mediated by a vegetarian diet, socioeconomic status, formaldehyde, thyroid function, or loss of teeth...
November 2017: Proceedings of the Nutrition Society
https://www.readbyqxmd.com/read/29136471/below-room-temperature-c-h-bond-breaking-on-an-inexpensive-metal-oxide-methanol-to-formaldehyde-on-ceo2-111
#12
Jonathan E Sutton, Thomas Danielson, Ariana Beste, Aditya Savara
Upgrading of primary alcohols by C-H bond breaking currently requires temperatures of >200 °C. In this work, new understanding from simulation of a temperature-programmed reaction study with methanol over a CeO2(111) surface shows C-H bond breaking and the subsequent desorption of formaldehyde, even below room temperature. This is of particular interest because CeO2 is a naturally abundant and inexpensive metal oxide. We combine density functional theory and kinetic Monte Carlo methods to show that the low-temperature C-H bond breaking occurs via disproportionation of adjacent methoxy species...
November 15, 2017: Journal of Physical Chemistry Letters
https://www.readbyqxmd.com/read/29136029/a-structural-review-of-foliar-glands-in-passiflora-l-passifloraceae
#13
Renata Cristina Cassimiro de Lemos, Delmira da Costa Silva, Gladys Flavia de Albuquerque Melo-de-Pinna
Extrafloral glands in Passifloraceae species have aroused the interest of many researchers because of their wide morphological diversity. The present work analyzed the foliar glands on 34 species of Passiflora from samples containing glands in the petiole and foliar blade fixed in 50% solution of formaldehyde-ethanol-acetic acid and stored in a 70% ethanol solution. For anatomical analyses, part of the material was embedded in Paraplast, longitudinally sectioned and double stained with safranin and astra blue...
2017: PloS One
https://www.readbyqxmd.com/read/29131468/oxidative-dissolution-of-resoles-a-versatile-approach-to-intricate-nanostructures
#14
Min Zhang, Hao Song, Yannan Yang, Xiaodan Huang, Yang Liu, Chao Liu, Chengzhong Yu
Resoles are base-catalyzed phenol-formaldehyde resins with a 3-dimensional cross-linked framework. The chemistry of resoles is generally considered as highly chemical resistant, thus calcination is always used in the treatment of resole-type resin, which significantly limit the diversity of nanostructured materials derived from resole-type resins. Here we report that selected metal nitrate solutions can be applied to dissolve various types of nanostructured resoles through an oxidative dissolution mechanism...
November 13, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/29131221/organocatalysis-using-aldehydes-the-development-and-improvement-of-catalytic-hydroaminations-hydrations-and-hydrolyses
#15
Bin-Jie Li, Claudia Ei-Nachef, André M Beauchemin
Organocatalysis has emerged as a powerful approach to facilitate and accelerate various difficult reactions. This Feature article presents recent developments and improvements using aldehydes as catalysts in difficult Cope-type intermolecular hydroamination, hydration and hydrolysis reactions. Most reactions exploit temporary intramolecularity. In catalytic Cope-type hydroaminations of allylic amines, aldehydes act as tethering catalysts, and allow room temperature reactions and high enantio- or diastereoselectivities if chiral aldehydes or reagents are used...
November 13, 2017: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/29126635/on-road-and-laboratory-emissions-of-no-no2-nh3-n2o-and-ch4-from-late-model-eu-light-utility-vehicles-comparison-of-diesel-and-cng
#16
Michal Vojtíšek-Lom, Vít Beránek, Vojtěch Klír, Petr Jindra, Martin Pechout, Tomáš Voříšek
Exhaust emissions of eight Euro 6 light duty vehicles - two station wagons and six vans - half powered by diesel fuel and half by compressed natural gas (CNG) were examined using both chassis dynamometer and on-road testing. A portable on-board FTIR analyzer was used to measure concentrations of reactive nitrogen compounds - NO, NO2 and ammonia, of CO, formaldehyde, acetaldehyde and greenhouse gases CO2, methane and N2O. Exhaust flow was inferred from engine control unit data. Total emissions per cycle were compared and found to be in good agreement with laboratory measurements of NOX, CO and CO2 during dynamometer tests...
November 7, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/29126066/formaldehyde-regulates-vascular-tensions-through-nitric-oxide-cgmp-signaling-pathway-and-ion-channels
#17
Quanxi Zhang, Peiru Tian, Miaomiao Zhai, Xiaodong Lei, Zhenhua Yang, Yan Liu, Mengting Liu, Hao Huang, Xiri Zhang, Xu Yang, Yun Zhao, Ziqiang Meng
Formaldehyde (FA) has been linked to the detrimental cardiovascular effects. Here, we explored the effects and mechanisms of FA on rat aortas both in vivo and in vitro. The results presented that FA evidently lowered the blood pressures of rats. The expression levels of BKCa subunits α and β1 and iNOS of the aortas were up-regulated by FA in vivo. However, FA markedly reduced the levels of Cav1.2 and Cav1.3, which are the subunits of L-Ca(2+) channel. Furthermore, the contents of NO, cGMP and iNOS in the aortas were augmented by FA...
November 4, 2017: Chemosphere
https://www.readbyqxmd.com/read/29124891/the-diagnostic-value-of-tissue-button-technique-for-specimen-accusation-during-endobronchial-ultrasound-guided-transbronchial-fine-needle-aspiration
#18
Oren Fruchter, Anna Breslavsky, Tatyana Brozgol, Anna Grossman, Kessi Mikhailova, Alexey Bugayov, Kassa Shimelis, Hananya Vaknine, Oleg Sukmanov
INTRODUCTION: The quality of tissue acquisition during Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) is a major determinant of the diagnostic yield of the procedure. In the tissue button (TB ) technique the retrieved cellular specimen is fixed in ethanol and subsequently scraped from slide using surgical blade into formaldehyde and processed like ordinary tissue biopsy thus potentially increasing its diagnostic value. OBJECTIVES: To retrospectively evaluate the diagnostic yield of a TB technique in patients undergoing EBUS-TBNA for various malignant and benign conditions...
November 10, 2017: Clinical Respiratory Journal
https://www.readbyqxmd.com/read/29121559/a-screen-printed-paper-microbial-fuel-cell-biosensor-for-detection-of-toxic-compounds-in-water
#19
Jon Chouler, Álvaro Cruz-Izquierdo, Saravanan Rengaraj, Janet L Scott, Mirella Di Lorenzo
Access to safe drinking water is a human right, crucial to combat inequalities, reduce poverty and allow sustainable development. In many areas of the world, however, this right is not guaranteed, in part because of the lack of easily deployable diagnostic tools. Low-cost and simple methods to test water supplies onsite can protect vulnerable communities from the impact of contaminants in drinking water. Ideally such devices would also be easy to dispose of so as to leave no trace, or have a detrimental effect on the environment...
November 6, 2017: Biosensors & Bioelectronics
https://www.readbyqxmd.com/read/29120619/a-rapid-throughput-method-to-extract-dna-from-formalin-fixed-paraffin-embedded-tissues-for-biomonitoring-carcinogenic-dna-adducts-in-humans
#20
Byeong Hwa Yun, Shun Xiao, Lihua Yao, Sesha Krishnamachari, Thomas A Rosenquist, Kathleen G Dickman, Arthur P Grollman, Paari Murugan, Christopher J Weight, Robert J Turesky
Formalin-fixed paraffin-embedded (FFPE) tissues are rarely used for screening DNA adducts of carcinogens because the harsh conditions required to reverse the formaldehyde-mediated DNA cross-links can destroy DNA adducts. We recently adapted a commercial silica-based column kit used in genomics to manually isolate DNA under mild conditions from FFPE tissues of rodents and humans and successfully measured DNA adducts of several carcinogens including aristolochic acid I (AA-I), 4-aminobiphenyl (4-ABP), and 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) (Yun et al...
November 9, 2017: Chemical Research in Toxicology
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